System for Deriving Electrical Characteristics and Non-Transitory Computer-Readable Medium

ABSTRACT

A system is provided in which electrical characteristics of an element formed on a sample can be evaluated. In order to achieve the above-described object, disclosed is a system including: an image acquisition tool; and a computer system that includes one or more processors and is configured to be communicable with the image acquisition tool, in which electrical characteristic are derived by receiving information regarding two or more characteristics of a specific pattern that is included in a plurality of images acquired from the image acquisition tool under at least two different image acquisition conditions and by referring to, for the information, relation information between information regarding two or more characteristics and electrical characteristics of an element formed on a sample, the characteristics being extracted from at least two pieces of image data acquired from the image acquisition tool under at least two image acquisition conditions.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. patent application Ser. No.16/885,727, filed May 28, 2020, which claims priority to Japanese PatentApplication No. 2019-136567, filed Jul. 25, 2019, the disclosures of allof which are expressly incorporated by reference herein.

TECHNICAL FIELD

The present disclosure relates to a system for deriving electricalcharacteristics and a non-transitory computer-readable medium, and, inparticular, relates to a system for deriving electrical characteristicsfrom a plurality of characteristics obtained under different imageacquisition conditions and a non-transitory computer-readable medium.

BACKGROUND ART

As one sample analysis method using an electron microscope, there isknown a method including: forming a voltage contrast image based ondetection of secondary electrons or the like obtained by irradiating asample with a pulsed electron beam; and evaluating electricalcharacteristics of an element formed on the sample based on analysis ofthe voltage contrast image.

PTL 1 describes a method of analyzing electrical characteristics of asample using a plurality of SEM images acquired under a plurality ofintermittent conditions. PTL 2 describes a method of analyzing a timeconstant of charge relaxation of a sample using a detection signal ofsecondary electrons obtained under a plurality of intermittentconditions. PTL 3 describes a method of analyzing a time constant ofcharge relaxation of a sample from a combined image of images acquiredunder a plurality of intermittent conditions.

CITATION LIST Patent Literature

PTL 1: Japanese Patent No. 6379018 (corresponding to U.S. Pat. No.9,659,744B)

PTL 2: Japanese Patent No. 5744629 (corresponding to U.S. Pat. No.8,907,279B)

PTL 3: Japanese Patent No. 6121651 (corresponding to U.S. Pat. No.9,236,220B)

SUMMARY OF INVENTION Technical Problem

PTLS 1 to 3 describe the methods of evaluating electricalcharacteristics of an element formed on a sample. However, if morespecific electrical characteristics can be evaluated instead of simplydetermining whether or not to be a defect, advanced process control canbe performed in a manufacturing process of a semiconductor device.Hereinafter, disclosed are: a system for deriving electricalcharacteristics in order to more appropriately evaluate electricalcharacteristics of an element formed on a sample; and a non-transitorycomputer-readable medium.

Solution to Problem

In order to achieve the above-described object, disclosed is a systemincluding: an image acquisition tool that acquires an image of a sample;a computer system that includes one or more processors and is configuredto be communicable with the image acquisition tool; and a memory thatstores relation information between information regarding two or morecharacteristics and electrical characteristics of an element formed on asample, the characteristics being extracted from at least two pieces ofimage data acquired from the image acquisition tool under at least twoimage acquisition conditions, in which the processor receivesinformation regarding two or more characteristics of a specific patternthat is included in a plurality of images acquired from the imageacquisition tool under at least two different image acquisitionconditions, receives the relation information from the memory, andderives the electrical characteristics by referring to the relationinformation for the information regarding the characteristics.

In addition, disclosed is a non-transitory computer-readable mediumstoring a program which causes a computer to execute the above-describedprocesses.

Further, disclosed is a system for estimating electrical characteristicsof an element formed on a sample from image data acquired from an imageacquisition tool, the system including: a computer system; and anarithmetic module that is executed by the computer system, in which thecomputer system includes a learning device that outputs the electricalcharacteristics of the element as a learning result, the learning deviceexecutes learning in advance using teacher data including at least oneamong at least two pieces of image data acquired from the imageacquisition tool under at least two image acquisition conditions, two ormore characteristics extracted from the two or more pieces of imagedata, and information generated from the two or more characteristics, atleast two image acquisition conditions of the image acquisition tool,and electrical characteristics, and the arithmetic module outputs theelectrical characteristics by inputting, to the learning device, atleast one among at least two pieces of image data acquired from theimage acquisition tool under at least two image acquisition conditions,two or more characteristics extracted from the two or more pieces ofimage data, and information generated from the two or morecharacteristics, and at least two image acquisition conditions of theimage acquisition tool.

Advantageous Effects of Invention

With this configuration, electrical characteristics of an element formedon a sample can be appropriately evaluated.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram showing one example of a scanning electronmicroscope.

FIG. 2 is a diagram showing a cross-sectional structure of a sampleaccording to Embodiment 1.

FIG. 3 is a flowchart showing one example of an inspection recipesetting process.

FIG. 4 is a diagram showing one example of an operation interface in theinspection recipe setting process.

FIG. 5 is a flowchart showing one example of an inspection process.

FIG. 6 is a diagram showing one example of an operation interface in theinspection process.

FIG. 7 is a diagram showing a cross-sectional structure of a sampleaccording to Embodiment 2.

FIG. 8 is a diagram showing one example of an operation interface in theinspection recipe setting process.

FIG. 9 is a diagram showing one example of an operation interface in theinspection process.

FIG. 10 is a diagram showing a cross-sectional structure of a sampleaccording to Embodiment 3.

FIG. 11 is a flowchart showing one example of the inspection recipesetting process.

FIG. 12 is a diagram showing one example of a method of calculating acorrection value of brightness of an image relative to a leakagecurrent.

FIG. 13 is a diagram showing one example of an operation interface inthe inspection recipe setting process.

FIG. 14 is a diagram showing a cross-sectional structure of a sampleaccording to Embodiment 4.

FIG. 15 is a flowchart showing one example of the inspection recipesetting process.

FIG. 16 is a diagram showing one example of a method of calculating acorrection value of brightness of an image relative to a leakage currentand a residual charge.

FIG. 17 is a diagram showing one example of an operation interface inthe inspection recipe setting process.

FIGS. 18A and 18B are graphs showing a change of brightness relative toa change of a blocking time of a beam.

FIG. 19 is a flowchart showing a process of deriving electricalcharacteristics using a scanning electron microscope.

FIG. 20 is a diagram showing one example of an electrical characteristicestimation system.

FIGS. 21A to 21D are cross-sectional views of a transistor formed on asemiconductor wafer.

FIG. 22 is a flowchart showing a process of deriving electricalcharacteristics using a scanning electron microscope.

FIGS. 23A to 23D are diagrams illustrating a change of brightness when abeam irradiation condition (image acquisition condition) is changed.

FIGS. 24A and 24B are graphs showing a change of brightness of a patternwhen the beam irradiation condition is changed.

FIG. 25 is a diagram illustrating input data to be input to a learningdevice that estimates electrical characteristics.

DESCRIPTION OF EMBODIMENTS

A charged particle beam apparatus, for example, a scanning electronmicroscope (SEM) is an apparatus capable of image formation,measurement, inspection, and the like of a fine pattern in the order ofnanometer using a focused electron beam. One observation method using aSEM is a voltage contrast method. The voltage contrast is a contrast onwhich a difference in surface voltage caused by charging during electronbeam irradiation is reflected, and can be used mainly for inspection orthe like of an electrical characteristic defect of a semiconductordevice. It is presumed that, in order to inspect an electricalcharacteristic defect, a defect position can be specified using adifference in brightness of a pattern of a SEM image. The brightness isa parameter indicating the degree of lightness of an image or a pixelacquired from a charged particle beam apparatus. In order to improve thedetection sensitivity of a defect using a voltage contrast, it isimportant to control accumulation and relaxation of charge duringelectron beam irradiation.

In the embodiment described below, an example in which a SEM image isacquired using a pulsed electron beam for the purpose of high-accuracycontrol of charging will be described. Here, the pulsed electron beamwill be referred to as a pulsed electron, and an intermittent conditionrefers to an irradiation time of the pulsed electron, an irradiationdistance of the pulsed electron, a blocking time between irradiation andirradiation, or an inter-irradiation point distance that is a distanceinterval between irradiation and irradiation.

On the other hand, in a defect inspection of a semiconductor deviceusing a SEM, high-accuracy process control can be realized byclassifying or evaluating a defect based on more specific electricalcharacteristics such as an electrical resistance R or a capacitance C,in addition to specifying a defect position using a difference inbrightness. For example, when defects can be classified based on theelectrical resistance R and the capacitance C, the defects can beclassified into a short-circuit defect having a lower electricalresistance R compared to a normal semiconductor device and a depletioncapacitance defect having a higher capacitance C compared to a normalsemiconductor device, and the amount of information to be fed back toprocess control increases. That is, in order to appropriately evaluatean electrical defect, it is desirable to independently analyzeelectrical parameters such as the electrical resistance R or thecapacitance C.

In the embodiment described below, a charged particle beam apparatusthat can independently evaluate at least one of a parametercorresponding to the electrical resistance R and a parametercorresponding to the capacitance C will be described. In the embodimentdescribed below, not only an RC time constant that is the product of theelectrical resistance R and the capacitance C but also an electricalparameter such as the electrical resistance R and the capacitance C canbe independently specified.

In a state where the accumulation of charge is steady, brightness S of avoltage contrast image is inversely proportional to the electricalresistance R and obeys Ohm's law as shown in Expression 1.

$\begin{matrix}{S \propto \frac{V_{s}}{R}} & \left\lbrack {{Expression}1} \right\rbrack\end{matrix}$

Here, Vs represents a surface voltage when charge is saturated andrepresents a charged state obtained under an intermittent conditionhaving a long irradiation time. When charge is saturated, the surfacevoltage is substantially constant. Therefore, as the electricalresistance R decreases, the brightness S of an image increases, and asthe electrical resistance R increases, the brightness S of an imagedecreases.

On the other hand, when charge is in a transient state, the brightness Sof an image is proportional to the capacitance C and is represented byExpression 2.

$\begin{matrix}{S \propto \left\{ {\frac{Q\left( {Tir} \right)}{C} + {\frac{Q({Tir})}{C}e^{{- {Ti}}/{RC}}}} \right\}^{- 1}} & \left\lbrack {{Expression}2} \right\rbrack\end{matrix}$

Here, Q represents a charge absorbed by a sample during electron beamirradiation, Tir represents an irradiation time, Ti represents ablocking time between irradiation and irradiation, and RC represents atime constant. Under an intermittent condition where the blocking timeTi between irradiation and irradiation is sufficiently long relative toRC, Expression 2 can be approximated to Expression 3.

$\begin{matrix}{S \propto \frac{C}{Q\left( {Tir} \right)}} & \left\lbrack {{Expression}3} \right\rbrack\end{matrix}$

The absorbed charge is constant irrespective of electricalcharacteristics. Therefore, as the capacitance C increases, thebrightness S of an image increases, and as the capacitance C decreases,the brightness S of an image decreases.

In addition, a difference between brightness ΔS that is extracted froman image acquired by beam scanning under a condition (first intermittentcondition) where the blocking time between irradiation and irradiationis Ti1 and brightness that is extracted from an image acquired by beamscanning under a condition (second intermittent condition) where theblocking time between irradiation and irradiation is Ti2 can berepresented by Expression 4.

$\begin{matrix}{{\Delta S} \propto {\frac{C}{Q\left( {Tir} \right)}\left( {e^{{- {Ti}}{1/{RC}}} - e^{{- {Ti}}{2/{RC}}}} \right)}} & \left\lbrack {{Expression}4} \right\rbrack\end{matrix}$

As shown in Expression 4, the difference ΔS in image brightnessrepresents a change amount of brightness depending on the RC timeconstant. When the RC time constant has the same time order as that ofthe blocking time Ti1 or Ti2, the difference ΔS in brightness increases.In addition, the RC time constant, the electrical resistance R, and thecapacitance C have a relationship of Expression 5.

RC=R×C  [Expression 5]

The present disclosure has been made based on a new finding relating toa relationship between charging caused by electron beam irradiation andelectrical characteristics of an element formed on a sample, and mainlyrelates to a method, a system, and a non-transitory computer-readablemedium described below. The system includes a computer system thatexecutes arithmetic processing based on an image signal or acharacteristic amount output from the charged particle beam apparatus.

In addition, the charged particle beam apparatus including the computersystem will also be described.

For example, in the following embodiment, a charged particle beamapparatus will be described, the apparatus including: a charged particlesource; means for pulsing a charged particle beam emitted from thecharged particle source; a charged particle beam optical system thatconvergently irradiates a sample with the pulsed charged particle beamwhile scanning with the beam; a secondary charged particle detectionsystem that detects secondary charged particles emitted from the sample;means for forming an image based on an intensity of a detection signalof the secondary charged particles; an intermittent irradiation systemthat controls an intermittent condition of the pulsed charged particlebeam such as an irradiation time or a blocking time between irradiationand irradiation; and an image processing system including a processorthat independently specifies a plurality of electrical characteristicsfrom brightness of the image obtained under a plurality of intermittentconditions, in which one of R and C is analyzed based on an imagebrightness under a first intermittent condition, an RC time constant isanalyzed based on a difference in image brightness between the firstintermittent condition and a second intermittent condition, and anotherone of R or C is analyzed based on one of R or C and the RC timeconstant such that the electrical characteristics can be independentlyspecified.

With the above-described configuration, the electrical resistance andthe capacitance based on application of an appropriate arithmeticexpression can be obtained. In addition, in the embodiment describedbelow, a defect position can be specified using a difference inbrightness, and electrical characteristics including the electricalresistance R and the capacitance C can be independently specified. As aresult, defects having different electrical characteristics such as ashort-circuit defect or a defect with abnormal depletion capacitance canbe classified.

Hereinafter, a charged particle beam apparatus that independentlyspecifies the electrical resistance R and the capacitance C aselectrical characteristics of a sample based on brightness of an imageobtained by intermittent irradiation of a charged particle beam will bedescribed with reference to the drawings.

In the following description, a scanning electron microscope thatirradiates a sample with an electron beam and detects secondaryelectrons to form an image will be described as one example of a chargedparticle beam apparatus that irradiates a sample with a charged particlebeam and detects secondary charged particles to form an image, but thepresent disclosure is not limited thereto. For example, an ion beamapparatus that irradiates a sample with an ion beam and detectssecondary ions or secondary electrons to form an image can also be usedas the image acquisition tool.

Embodiment 1

In the present embodiment, regarding a defect inspection apparatus thatclassifies and inspects defects of a sample having different electricalcharacteristics using an image of a scanning electron microscope, ascanning electron microscope having a function of independentlyanalyzing the electrical resistance R and the capacitance C of defectsfrom brightness of images acquired under a plurality of intermittentconditions will be described.

FIG. 1 shows one example of the scanning electron microscope accordingto the present embodiment. The scanning electron microscope isconfigured with an intermittent irradiation system, an electron opticalsystem, a secondary electron detection system, a stage mechanism system,an image processing system, a control system, and an operation system.The intermittent irradiation system is configured with an electron beamsource 1 and a pulsed electron generator 4. In the present invention,the pulsed electron generator 4 is separately provided. However, anelectron beam source that can irradiate a pulsed electron can also beused.

The electron optical system is configured with a condenser lens 2, adiaphragm 3, a deflector 5, an objective lens 6, and a sample electricfield controller 7. The deflector 5 is provided to one-dimensionally ortwo-dimensionally scan the sample with the electron beam and is a targetto be controlled as described below.

The secondary electron detection system is configured with a detector 8and an output adjustment circuit 9. The stage mechanism system isconfigured with a sample stage 10 and a sample 11. The control system isconfigured with an acceleration voltage controller 21, an irradiationcurrent controller 22, a pulse irradiation controller 23, a deflectioncontroller 24, a focusing controller 25, a sample electric fieldcontroller 26, a stage position controller 27, and a control transmitter28. The control transmitter 28 controls writing of a control value toeach of the controllers based on input information input from anoperation interface 41.

Here, the pulse irradiation controller 23 controls an irradiation timethat is a time for which an electron beam is continuously irradiated, anirradiation distance that is a distance by which an electron beam iscontinuously irradiated, a blocking time that is a time betweenirradiation and irradiation of an electron beam, or an inter-irradiationpoint distance that is a distance interval between irradiation andirradiation of an electron beam. In the present embodiment, the pulseirradiation controller 23 controls the irradiation time that is a timefor which an electron beam is continuously irradiated and the blockingtime that is a time between irradiation and irradiation of an electronbeam.

The pulse irradiation controller 23 controls a scanning deflector thatscans the sample with a beam and a blanking deflector that blocksirradiation of a sample with a beam such that a pulsed beam isgenerated. During beam irradiation by the scanning deflector, a blankingelectrode generates a pulsed beam by intermittently blocking a beamaccording to a set irradiation condition.

The image processing system is configured with a detection signalprocessing unit 31, a detection signal analysis unit 32, an image orelectrical characteristic display unit 33, and a database 34. Thedetection signal processing unit 31 or the detection signal analysisunit 32 of the image processing system includes one or more processorsand executes an arithmetic operation of brightness of a designatedinspection pattern, an arithmetic operation of a difference inbrightness between a plurality of inspection patterns, or an arithmeticoperation of analyzing or classifying electrical characteristics basedon brightness or a difference in brightness. The database 34 of theimage processing system is a storage medium that stores calibration datawhen the arithmetic operation or the like of analyzing electricalcharacteristics is executed such that the calibration data is read andused during the arithmetic operation.

The operation system is configured with the operation interface 41. FIG.2 is a cross-sectional view of a sample used in the present embodiment.A plug 51 is in contact with a wiring 52 that is electrically floatingfrom a silicon substrate 53. A plug 54 is a defective plug that is notin contact with the wiring 52 at all. A plug 55 is a defective plug thathas an electrical resistance and is coupled to the wiring 52. In thepresent embodiment, the above-described two types of defects areclassified and inspected.

The above-described control, image processing, and the like are executedby one or more computer systems including one or more processors. Theone or more computer systems are configured to execute an arithmeticmodule stored in a predetermined storage medium in advance, andautomatically or semi-automatically execute a process as describedbelow. Further, the one or more computer systems are configured to becommunicable with the image acquisition tool.

FIG. 3 is a flowchart showing an inspection recipe setting process ofindependently analyzing the electrical resistance R and the capacitanceC of a defect in the present embodiment.

First, a sample moves to an observation place (S101). Next, a layout ofa sample to be inspected is designated (S102). Here, the layout is alayout of a repeated pattern region of a semiconductor wafer. Next, thesample moves to a trial inspection region used for generating the recipeusing layout information (S103). Next, an optical condition is set(S104).

Here, the optical condition includes an acceleration voltage of anelectron beam, an irradiation current of an electron beam, and ascanning speed. Next, a size of a field of view of observation or anobservation magnification is set (S105). Next, a plurality ofintermittent conditions are set and an image is acquired (S106). Theplurality of intermittent conditions set in S106 are different from eachother in at least one condition among the irradiation time, theirradiation distance, the blocking time, or the inter-irradiation pointdistance. Further, the plurality of intermittent conditions set in S106have at least two different blocking times.

Next, the capacitance C or the electrical resistance R is analyzed basedon a saturated brightness value at which the brightness of the image issaturated at a plurality of intermittent times (S107). In S107 of thepresent embodiment, first, the brightness values of a plurality ofimages having different blocking times as intermittent conditions arecompared to each other, a first threshold and a second threshold are setfor a change amount of the brightness of the image depending on a changeof the blocking time, and the brightness of the image at a blocking timeat which the change amount of the brightness is the first threshold orless is set as the saturated brightness value. In addition, in S107 ofthe present embodiment, the capacitance is analyzed (calculated) basedon Expression 3.

Next, the RC time constant is analyzed using a difference value ofbrightness of a plurality of images acquired under a plurality ofintermittent conditions (S108). In S108 of the present embodiment, theRC time constant is analyzed based on Expression 4. Here, it isdesirable that ΔS represents a difference between the saturatedbrightness value and a brightness (for example, corresponding to a peakposition by differential processing) at which the change amount ofbrightness is maximum and the blocking times Ti1 and Ti2 represent ablocking time having the saturated brightness value and a blocking timeat which the change amount of brightness is maximum, respectively.

Next, the electrical resistance R or the capacitance C is analyzed fromthe analyzed capacitance and RC time constant or analyzed resistance andRC time constant (S109). Here, a parameter that is not calculated inS107 is calculated.

In S109 of the present embodiment, the electrical resistance R isanalyzed based on Expression 5. The intermittent conditions and theresults of brightness of the image or the electrical resistance R andthe capacitance C obtained in the trial inspection are displayed (S110).

Next, two or more intermittent conditions used for the inspection areset (S111). In the present embodiment, the apparatus automaticallyextracts a blocking time as a first intermittent condition at which thechange amount of the brightness is the first threshold or less and ablocking time as a second intermittent condition at which the changeamount of the brightness is the second threshold or less from theintermittent conditions used in the trial inspection, respectively.Next, the inspection recipe generation process ends (S112).

As described above, by using a computer system and an arithmetic modulethat are configured to calculate one of a first characteristic (forexample, R) or a second characteristic (for example, C) of an elementformed on a sample by inputting another one of the first characteristicor the second characteristic, a plurality of irradiation conditions of abeam (for example, a plurality of blocking times), and comparisoninformation (ΔS) of characteristic amounts during beam irradiation undera plurality of irradiation conditions into relation information (forexample, Expression 3) of the first characteristic, the secondcharacteristic, the plurality of irradiation conditions of a beam (forexample, the intermittent time), and the comparison information (ΔS),the two characteristics can be appropriately evaluated based onselection of an appropriate arithmetic expression corresponding to theelement.

Whether a defect is a capacitance defect or an electrical resistancedefect can also be determined from a characteristic of a change ofbrightness when a plurality of beam blocking conditions are set. Here,the capacitance defect refers to a defect in which the electricalresistances are almost the same but the capacitances are different fromeach other among a plurality of patterns in a region of interest (ROI).On the other hand, the electrical resistance defect refers to a defectin which the capacitances are almost the same but the electricalresistances are different from each other among a plurality of patternsin the ROI.

FIG. 18 is a graph showing a change of brightness relative to a changeof the blocking time (time for which a pulsed beam is not irradiated),in which (a) of FIG. 18 shows a change of brightness relative to achange of the blocking time of the capacitance defect and (b) of FIG. 18shows a change of brightness relative to a change of the blocking timeof the electrical resistance defect. As shown in FIG. 18 , theelectrical resistance defect and the capacitance defect are differentfrom each other in the characteristic of the change of brightness whenthe blocking time is changed. Accordingly, whether a defect is acapacitance defect or an electrical resistance defect may be determinedbased on the difference in the characteristic.

In addition, in the case of the capacitance defect, as the blocking timeincreases, the difference of brightness for each capacitance tends toget larger. By using this characteristic, a defect type may bedetermined from, for example, a difference between brightness in casethat the blocking time is long and a previously registered averagebrightness value (an average brightness value of different capacitancedefects) in case that the blocking time is long. In this case, forexample, it is thought that when the difference exceeds a predeterminedthreshold, the defect is determined to be a capacitance defect, and whenthe difference is the predetermined threshold or less, the defect isdetermined to be an electrical resistance defect.

In addition, in the case of the electrical resistance defect, as theblocking time decreases, the difference of brightness for eachelectrical resistance tends to become clear. By using thischaracteristic, a defect type may be determined from, for example, adifference between brightness in case that the blocking time is shortand a previously registered average brightness value (an averagebrightness value of different electrical resistance defects) in casethat the blocking time is short. In this case, for example, it isthought that when the difference exceeds a predetermined threshold, thedefect is determined to be an electrical resistance defect, and when thedifference is the predetermined threshold or less, the defect isdetermined to be a capacitance defect.

In addition, by fitting the obtained curve to a curve representing arelationship between a change of the blocking time and a change ofbrightness that is stored in advance for each defect type, a defect typemay be classified according to the degree of coincidence of the curves.Further, it is also thought that a plurality of curves corresponding toa plurality of capacitances and a plurality of curves corresponding to aplurality of electrical resistances are prepared (stored) in advance toestimate a capacitance or an electrical resistance according to thedegree of coincidence thereof.

As described above, when the defect is determined to be the capacitancedefect, C may be obtained using Expression 3 in S107, and when thedefect is determined to be the electrical resistance defect as describedabove, R may be obtained using Expression 1.

FIG. 19 is a flowchart showing a process for determining the type ofelectrical characteristics or the characteristic amount. As in Step 106of FIG. 3 , an image is formed at each of a plurality of blocking times(Steps 1901 and 1902), a set number of images (blocking conditions) areacquired, a curve (function) representing a change of the blocking timeand a change of the characteristic amount (brightness) extracted fromthe images is generated (Step 1903), the curve is compared to referencedata in which the defect type or the characteristic amount (capacitanceand electrical resistance) of a defect are stored in association witheach other (Step 1904), and at least one of the defect type and thecharacteristic amount of a defect is specified (Step 1905). The curve isinformation generated from two or more characteristics that areextracted from two or more pieces of image data acquired under aplurality of image acquisition conditions having different irradiationconditions. In the following embodiment, this curve will also bereferred to as an S-curve.

The type or a characteristic of a defect can be derived by referencingthis information to relation information between information, that isgenerated from two or more characteristics extracted from at least twopieces of image data acquired under two or more image acquisitionconditions, and at least one of the type of a defect of an elementformed on an sample and the characteristics of the defect (electricalcharacteristic).

In the computer system that can execute the process as shown in FIG. 19, not only whether or not a defect is present but also the type andcharacteristic amount of the defect can be specified.

FIG. 4 shows an operation interface in the inspection recipe settingprocess used in the present embodiment. The operation interface displaysa SEM image and includes an inspection pattern setting unit 61 fordesignating an inspection pattern of which electrical characteristicsare analyzed from a trial inspection image. In the present embodiment, apattern a and a pattern b are selected. In addition, the operationinterface includes an optical condition/scanning condition/field of viewsetting unit 62, an acceleration voltage setting unit 63, an irradiationcurrent setting unit 64, a field-of-view size setting unit 65, and ascanning speed setting unit 66. In the present embodiment, theacceleration voltage is set to 500 V, the irradiation current is set to100 pA, the size of the field of view is set to 3 μm, and the scanningspeed is set to a TV rate.

In addition, an intermittent condition extraction unit 67, which sets aplurality of intermittent conditions and analyzes the intermittentcondition dependence of the brightness of a pattern selected by theinspection pattern setting unit 61, includes:

an irradiation setting unit 68 that sets an irradiation time or anirradiation distance; an inter-irradiation point setting unit 69 thatsets a blocking time between irradiation points or a distance betweenirradiation points; and a brightness analysis result display unit 70that displays the intermittent condition dependence of the brightness ofthe pattern. In the present embodiment, the irradiation setting unit 68is configured to set the irradiation time, and the inter-irradiationpoint setting unit 69 is configured to set the blocking time.

In addition, in the present embodiment, six conditions can be set as theplurality of intermittent conditions, and the plurality of intermittentconditions include a normal condition that is normal scanning. As theplurality of intermittent conditions, the irradiation time is set to 0.3μs, and the blocking times are set to 0.1, 0.2, 0.7, 1.2, and 1.7 μs,respectively.

In addition, an inspection condition setting unit 71, which sets aplurality of intermittent conditions used for the inspection anddisplays the analysis results of the electrical resistance R and thecapacitance C in the trial inspection, includes: an irradiation settingunit 72 that sets an irradiation time or an irradiation distance usedfor the inspection; an inter-irradiation point setting unit 73 that setsa blocking time between irradiation points or a distance betweenirradiation points used for the inspection; a trial inspection executionunit 74 that executes the trial inspection; and a trial inspectionresult display unit 75 in which the electrical resistance R and thecapacitance C in the trial inspection are displayed.

In the present embodiment, as the intermittent conditions used for theinspection, a first intermittent condition in which an irradiation timeis 0.3 μs and a blocking time is 1.7 μs and a second intermittentcondition in which an irradiation time is 0.3 μs and a blocking time is0.1 μs are extracted, and the capacitance C is analyzed based onExpression 3 using the brightness of the image acquired under the firstintermittent condition. In addition, in the present embodiment, thecapacitance C is analyzed using the relationship between the brightnessand the capacitance C as the calibration data that is stored in thedatabase 34 shown in FIG. 1 in advance.

In addition, in the present embodiment, the RC time constant is analyzedbased on Expression 4 using a difference in brightness between the imageacquired under the first intermittent condition and the image under thesecond intermittent condition.

FIG. 5 is a flowchart showing the inspection process of independentlyanalyzing the electrical resistance R and the capacitance C of a defectto classify the defect. First, the inspection recipe generated in theflowchart of FIG. 3 is read (S121). Next, a region to be inspected isdesignated (S122). Next, the optical condition read from the inspectionrecipe is set from the control transmitter 28 (S123). Next, a pluralityof intermittent conditions are set (S124). Next, the sample moves to aninspection place (S125). Next, images are acquired under a plurality ofintermittent conditions (S126).

In the present embodiment, images are acquired under the firstintermittent condition and the second intermittent condition set in theinspection recipe. Next, the brightness of an image is analyzed under asingle intermittent condition (S127). In the present embodiment, thebrightness of the image is analyzed under the first intermittentcondition. Next, the capacitance C or the electrical resistance R isanalyzed based on the image brightness acquired under the singleintermittent condition (S128). In the present embodiment, thecapacitance C is analyzed based on Expression 3 using the brightness ofthe image acquired under the first intermittent condition.

Next, a difference in brightness between images acquired under aplurality of intermittent conditions is analyzed (S129). In the presentembodiment, a difference in brightness between the images acquired underthe first intermittent condition and the second intermittent conditionis analyzed. Next, the RC time constant is analyzed based on thedifference value of the pattern brightness (S130). In the presentembodiment, the RC time constant is analyzed based on Expression 4.

Next, another electrical characteristic value (the value of anelectrical characteristic different from the previously obtainedelectrical characteristic) is analyzed using the capacitance C or theelectrical resistance R obtained in S128 and the RC time constantobtained in S130 (S131). In the present embodiment, the capacitance C isobtained in advance in S128. Therefore, the electrical resistance R isanalyzed using Expression 5 from the capacitance C and the RC timeconstant obtained in S130. In the designated inspection region, StepsS125 to S131 are repeated. Next, the results of the electricalresistance and the capacitance are displayed (S132). Next, the type of adefect is classified from the results of the electrical resistance andthe capacitance (S133). Next, a generating state in a wafer surface isdisplayed as the classified result (S134). In the present embodiment, anaverage defect density or the like is also displayed as the inspectionresult. Next, the inspection process ends (S135).

FIG. 6 shows an operation interface in a defect inspection process usedin the present embodiment. The operation interface includes aninspection region setting unit 81 that sets the inspection region, andincludes an inspection execution unit 82 that reads the inspectionrecipe generated in the flowchart of FIG. 3 and executes the inspection.In addition, the operation interface includes a defect classificationsetting unit 83 that displays the inspection results of the electricalresistance R and the capacitance C and classifies defects based on theinspection results. In the present embodiment, defects are classifiedinto a defect a group having a high electrical resistance R and a lowcapacitance C and a defect b group having a low electrical resistance Rand a high capacitance C. The defect a group corresponds to a defectiveplug of the plug 54 of FIG. 2 , and the defect b group corresponds to adefective plug of the plug 55 of FIG. 2 .

In addition, the operation interface includes: a defect a groupgenerating distribution display unit 84 that displays an in-waferdistribution of the classified defect a group or an average defectdensity thereof; and a defect b group generating distribution displayunit 85 that displays an in-wafer distribution of the classified defectb group or an average defect density thereof.

In the above-described embodiment, the electrical resistance R and thecapacitance C can be independently analyzed under a plurality ofintermittent conditions. With this analysis, defects can be classifiedbased on the electrical resistance R and the capacitance C, and thegenerating status of the classified defects can be provided.

Embodiment 2

In the present embodiment, regarding a defect inspection apparatus thatclassifies and inspects defects of a sample having different electricalcharacteristics using an image of a scanning electron microscope, ascanning electron microscope having a function of independentlyanalyzing the electrical resistance R and the capacitance C of defectsfrom brightness of images acquired under a plurality of intermittentconditions will be described.

In the present embodiment, the scanning electron microscope shown inFIG. 1 is used. FIG. 7 is a cross-sectional view of a sample used in thepresent embodiment. A plug 91 is a normal plug that is in contact withan impurity diffusion layer 93 formed on a part of a silicon substrate92. The silicon substrate 92 and the impurity diffusion layer 93 form aPN junction and have diode characteristics. A plug 94 is a defectiveplug that is in contact with the impurity diffusion layer with highresistance. A plug 95 is a defective plug that is not in contact withthe impurity diffusion layer at all. A plug 96 is a defective plug thatis in contact with the destructed impurity diffusion layer.

In the present embodiment, three types of defective plugs are classifiedand inspected. In the present embodiment, the flowchart of theinspection recipe setting process shown in FIG. 3 is used. In thepresent embodiment, in S107 shown in FIG. 3 , the electrical resistanceR is analyzed based on Expression 1. In addition, in the presentembodiment, in S109 shown in FIG. 3 , the capacitance C is analyzedbased on Expression 5.

FIG. 8 shows an operation interface in the inspection recipe settingprocess used in the present embodiment. The operation interface includesan inspection pattern setting unit 61 for displaying the SEM image shownin FIG. 4 and designating an inspection pattern of which electricalcharacteristics are analyzed from a trial inspection image. In thepresent embodiment, a pattern a, a pattern b, and a pattern c areselected as targets to be inspected. In addition, the operationinterface includes the optical condition/scanning condition/field ofview setting unit 62 shown in FIG. 4 , and the acceleration voltagesetting unit 63, the irradiation current setting unit 64, thefield-of-view size setting unit 65, and the scanning speed setting unit66 shown in FIG. 4 . In the present embodiment, the acceleration voltageis set to 1000 V, the irradiation current is set to 500 pA, the size ofthe field of view is set to 3 μm, and the scanning speed is set to a TVrate.

In addition, as shown in FIG. 4 , the operation interface includes theintermittent condition extraction unit 67 that sets a plurality ofintermittent conditions and analyzes the intermittent conditiondependence of the brightness of the pattern selected by the inspectionpattern setting unit 61. In the present embodiment, the irradiationsetting unit 68 is configured to set the irradiation time, and theinter-irradiation point setting unit 69 is configured to set theblocking time. In addition, in the present embodiment, six conditionscan be set as the plurality of intermittent conditions, and theplurality of intermittent conditions include a normal condition that isnormal scanning. As the plurality of intermittent conditions, theirradiation time is set to 0.1 μs, and the blocking times are set to0.1, 0.5, 1.0, 3.0, and 5.0 μs, respectively.

In addition, as shown in FIG. 4 , the operation interface includes theinspection condition setting unit 71 that sets a plurality ofintermittent conditions used for the inspection and displays theanalysis results of the electrical resistance R and the capacitance C inthe trial inspection.

In the present embodiment, as the intermittent conditions used for theinspection, a first intermittent condition as a normal condition, asecond intermittent condition in which an irradiation time is 0.1 μs anda blocking time is 0.1 μs, and a third intermittent condition in whichan irradiation time is 0.1 μs and a blocking time is 1.0 μs areextracted, and the electrical resistance R is analyzed based onExpression 1 using the brightness of the image acquired under the firstintermittent condition.

In addition, in the present embodiment, only the relative magnitude ofelectrical resistance R is analyzed, and the absolute value thereof isnot calibrated.

In addition, in the present embodiment, a first RC time constant isanalyzed based on Expression 4 using a difference in brightness betweenthe image acquired under the first intermittent condition and the imageacquired under the second intermittent condition, and a second RC timeconstant is analyzed based on Expression 4 using a difference inbrightness between the image acquired under the second intermittentcondition and the image under the third intermittent condition.

When the same defective plug has a plurality of RC time constants, afirst capacitance C and a second capacitance C can be analyzed from theelectrical resistance R, the first RC time constant, and the second RCtime constant. In the present embodiment, only for the pattern c, thefirst electrical resistance R and the capacitance C, and the secondelectrical resistance R and the capacitance C are output as theinspection result. In the present embodiment, the flowchart of theinspection process of classifying defects shown in FIG. 5 is used.

FIG. 9 shows an operation interface in a defect inspection process usedin the present embodiment. The operation interface includes theinspection region setting unit 81 that sets the inspection region, andincludes the inspection execution unit 82 that reads the inspectionrecipe generated in the flowchart of FIG. 3 and executes the inspection.In addition, the operation interface includes the defect classificationsetting unit 83 that displays the inspection results of the electricalresistance R and the capacitance C and classifies defects based on theinspection results.

In the present embodiment, defects are classified into a defect a grouphaving an intermediate electrical resistance R and an intermediatecapacitance C, a defect b group having a high electrical resistance Rand a low capacitance C, and a defect c group having the firstelectrical resistance R, the second electrical resistance R, and thecapacitance C. The defect a group corresponds to the defective plug ofthe plug 94 of FIG. 7 , the defect b group corresponds to the defectiveplug of the plug 95 of FIG. 7 , and the defect c group corresponds tothe defective plug of the plug 96 of FIG. 7 . In addition, the operationinterface includes a defect group generating distribution display unit86 that displays an in-wafer distribution of the classified defectgroups.

In the above-described embodiment, the electrical resistance R and thecapacitance C can be independently analyzed under a plurality ofintermittent conditions. With this analysis, defects can be classifiedbased on the electrical resistance R and the capacitance C, and thegenerating status of the classified defects can be provided.

Embodiment 3

In the present embodiment, regarding a defect inspection apparatus thatclassifies and inspects defects of a sample having different electricalcharacteristics using an image of a scanning electron microscope, ascanning electron microscope having a function of correcting thebrightness according to electrical characteristics and independentlyanalyzing the electrical resistance R and the capacitance C of defectswith high accuracy from brightness values of images acquired under aplurality of intermittent conditions will be described.

In the present embodiment, the scanning electron microscope shown inFIG. 1 is used.

FIG. 10 is a cross-sectional view of a sample used in the presentembodiment. A plug 101 is in contact with a wiring 104 that iselectrically floating from a silicon substrate 106. A plug 102 is adefective plug that is not in contact with the wiring 104. A plug 103 isa defective plug that penetrates the wiring 104 and is in contact with awiring 105 being positioned below the wiring 104 and being electricallyfloating. In the present embodiment, the normal plug and the two typesof defective plugs are classified and inspected.

FIG. 11 is a flowchart showing an inspection recipe setting process ofcorrecting the brightness according to electrical characteristics andindependently analyzing the electrical resistance R and the capacitanceC of defects with high accuracy in the present embodiment.

First, a sample moves to an observation place (S141). Next, a layout ofa sample to be inspected is designated (S142). Here, the layout is alayout of a repeated pattern region of a semiconductor wafer. Next, thesample moves to a trial inspection region used for generating the recipeusing layout information (S143). Next, an optical condition is set(S144). Here, the optical condition includes an acceleration voltage ofan electron beam, an irradiation current of an electron beam, and ascanning speed. Next, a size of a field of view of observation or anobservation magnification is set (S145). Next, a plurality ofintermittent conditions are set and an image is acquired (S146). Theplurality of intermittent conditions set in S146 are different from eachother in at least one condition among the irradiation time, theirradiation distance, the blocking time, or the inter-irradiation pointdistance. Further, the plurality of intermittent conditions set in S146have at least two different irradiation times.

Next, brightness of images acquired under a plurality of intermittentconditions is analyzed (S147). Next, the electrical resistance R isanalyzed based on a saturated brightness value at which the brightnessof the image is saturated at a plurality of irradiation times (S148). InS148 of the present embodiment, first, the brightness values of aplurality of images having different irradiation times are compared toeach other, a threshold is set for a change amount of the brightness ofthe image depending on a change of the irradiation time, and thebrightness of the image at an irradiation time at which the changeamount of the brightness is the threshold or less is set as thesaturated brightness value. In addition, In S107 of the presentembodiment, the electrical resistance is analyzed based on Expression 1.Next, the correction value of the brightness of the image relative to aleakage current is calculated based on the saturated brightness value ata plurality of irradiation times (S149). Next, the RC time constant isanalyzed using a difference value of corrected brightness obtained bysubtracting the correction value from the brightness of the imagesacquired under a plurality of intermittent conditions (S150).

Next, the capacitance C is analyzed from the electrical resistance R andthe RC time constant (S151). Next, the results of the intermittentconditions and the brightness of the image or the electrical resistanceR and the capacitance C obtained in the trial inspection are displayed(S152). Next, two or more intermittent conditions used for theinspection are set (S153). In the present embodiment, the user manuallysets the intermittent conditions.

However, the apparatus may automatically determine and set theintermittent conditions from the intermittent conditions used. Next, theinspection recipe generation process ends (S154).

FIG. 12 shows a method of calculating the correction value of thebrightness of the image relative to a leakage current in S149 in thepresent embodiment. It can be seen from a time change 111 of brightnessobtained at a first irradiation time, a time change 112 of brightnessobtained at a second irradiation time, and a time change 113 ofbrightness obtained at a third irradiation time that, as the irradiationtime increases, the brightness decreases due to charging of electronbeam irradiation. In addition, a decrease in brightness is saturated atthe third irradiation time. On the brightness at the third irradiationtime, a leakage current flowing due to an internal electric field of thesample during charging is reflected. As shown in a time change 114 ofbrightness obtained at the first to third irradiation times, in thepresent embodiment, this change of brightness caused by a leakagecurrent is linearly corrected. A corrected brightness Sc is representedby Expression 6.

$\begin{matrix}{{Sc} = {S - {{Tir} \times \frac{S_{S}}{T_{S}}\left( {0 \leq {Tir} \leq T_{S}} \right)}}} & \left\lbrack {{Expression}6} \right\rbrack\end{matrix}$

Here, S represents brightness, Tir represents an irradiation time, S_(s)represents brightness during saturation obtained at the thirdirradiation time, and T_(s) represents an irradiation time when adecrease in brightness is saturated, and corresponds to the thirdirradiation time. Here, S_(s) corresponds to S obtained in Expression 1.In a time change 115 of corrected brightness corrected using Expression6, the dependence of a leakage current is corrected. In addition, inS149, the correction value of brightness for obtaining ΔS in Expression4 is calculated. As shown in FIG. 12 , the irradiation time T_(s) duringthe saturation of brightness is obtained in advance from a curveobtained by changing the irradiation time and the detection timing(time). As a result, the correction using Expression 6 can be performed.

FIG. 13 shows an operation interface in the inspection recipe settingprocess used in the present embodiment. The operation interface has thesame configuration as that shown in FIG. 4 . In the present embodiment,a pattern a, a pattern b, and a pattern c are selected as targets to beinspected in the inspection pattern setting unit 61. In addition, in theacceleration voltage setting unit 63, the irradiation current settingunit 64, the field-of-view size setting unit 65, and the scanning speedsetting unit 66, the acceleration voltage is set to 300 V, theirradiation current is set to 1000 pA, the size of the field of view isset to 1 μm, and the scanning speed is set to a rate that is two times aTV rate.

In the present embodiment, five intermittent conditions are set in theirradiation setting unit 68 and the inter-irradiation point setting unit69. As the intermittent conditions, the irradiation times are set to0.1, 0.2, 0.3, 0.4, and 0.5 μs, respectively, and all the blocking timesare set to 5.0 μs. When a decrease in brightness is saturated, theirradiation time T_(s) is 0.5 μs, and the brightness S_(s) duringsaturation can be extracted from each of the pattern a, the pattern b,and the pattern c in the brightness analysis result display unit 70.

In the present embodiment, in the inspection condition setting unit 71,a first intermittent condition used for the inspection is set so that anirradiation time is 0.1 μs and a blocking time is 5.0 μs, a secondintermittent condition is set so that an irradiation time is 0.3 μs anda blocking time is μs, and a third intermittent condition is set so thatan irradiation time is 0.5 μs and a blocking time is 5.0 μs.

The electrical resistance R is analyzed based on Expression 1 from thebrightness obtained under the third intermittent condition. In thepresent embodiment, the corrected brightness is calculated using acorrection expression of Expression 6, and a first RC time constant isanalyzed based on Expression 4 using a difference in correctedbrightness between the image acquired under the first intermittentcondition and the image acquired under the second intermittentcondition. The capacitance C can be analyzed using Expression 5 from theelectrical resistance R and the RC time constant.

In the present embodiment, the flowchart of the inspection process ofclassifying defects shown in FIG. 5 is used. In the present embodiment,the operation interface of the defect inspection process shown in FIG. 9is used. Under the inspection conditions set in the inspection recipesetting process, the plug 101 as a normal plug, the plug 102 as adefective plug, and the plug 103 as a defective plug can be classifiedand inspected.

In the embodiment described above, by correcting the brightnessaccording to the electrical characteristics, the electrical resistance Rand the capacitance C of a defect can be analyzed with high accuracy.Therefore, the accuracy of defect classification is improved.

Embodiment 4

In the present embodiment, regarding a defect inspection apparatus thatclassifies and inspects defects of a sample having different electricalcharacteristics using an image of a scanning electron microscope, ascanning electron microscope having a function of correcting thebrightness according to electrical characteristics and independentlyanalyzing the electrical resistance R and the capacitance C of defectswith high accuracy from brightness of images acquired under a pluralityof intermittent conditions will be described.

In the present embodiment, the scanning electron microscope shown inFIG. 1 is used. FIG. 14 is a cross-sectional view of a sample used inthe present embodiment. A plug 121 is in contact with an impuritydiffusion layer 124 formed on a part of a silicon substrate 125 fromwhich an element is separated. A plug 122 is a defective plug that isnot in contact with the impurity diffusion layer 124. A plug 123 is adefective plug in which two adjacent plugs are electrically connected.In the present embodiment, the normal plug and the two types ofdefective plugs are classified and inspected.

FIG. 15 is a flowchart showing an inspection recipe setting process ofcorrecting the brightness according to electrical characteristics andindependently analyzing the electrical resistance R and the capacitanceC of defects with high accuracy in the present embodiment.

First, a sample moves to an observation place (S161). Next, a layout ofa sample to be inspected is designated (S162). Here, the layout is alayout of a repeated pattern region of a semiconductor wafer. Next, thesample moves to a trial inspection region used for generating the recipeusing layout information (S163). Next, an optical condition is set(S164). Here, the optical condition includes an acceleration voltage ofan electron beam, an irradiation current of an electron beam, and ascanning speed. Next, a size of a field of view of observation or anobservation magnification is set (S165). Next, a plurality ofintermittent conditions are set and an image is acquired (S166). Theplurality of intermittent conditions set in S166 are different from eachother in at least one condition among the irradiation time, theirradiation distance, the blocking time, or the inter-irradiation pointdistance. Further, the plurality of intermittent conditions set in S166have at least two different irradiation times and at least two differentblocking times.

Next, brightness of images acquired under a plurality of intermittentconditions is analyzed (S167). Next, the electrical resistance R isanalyzed based on a saturated brightness value at which the brightnessof the image is saturated at a plurality of irradiation times (S168).Next, the correction value of the brightness of the image relative to aresidual charge is calculated based on the saturated brightness value ata plurality of irradiation times (S169). Next, the capacitance C isanalyzed from the corrected brightness corrected using the correctionvalue relative to a residual charge (S170). Next, the results of theintermittent conditions and the brightness of the image or theelectrical resistance R and the capacitance C obtained in the trialinspection are displayed (S171). Next, two or more intermittentconditions used for the inspection are set (S172). In the presentembodiment, the user manually sets the intermittent conditions. However,the apparatus may automatically determine and set the intermittentconditions from the intermittent conditions used. Next, the inspectionrecipe generation process ends (S173).

FIG. 16 shows the correction result of the brightness of the imagerelative to a residual charge in S169 in the present embodiment. In thesample according to the present embodiment, charging is saturated at anelectron beam irradiation time of μs. In addition, in the presentembodiment, a leakage current flowing due to an internal electric fieldof the sample during charging is not considered. The time change of thebrightness S represents charge accumulation characteristics by electronbeam irradiation and can be represented by Expression 7.

S=S ₀ ×e ^(−Tir/τ)  [Expression 7]

Here, S₀ represents brightness at an irradiation time Tir of 0, Tirrepresents an irradiation time, τ represents a time constant of chargeaccumulation, and S₀ can be represented by Expression 7 whenapproximated to a line of the blocking time Ti.

$\begin{matrix}{S_{0} = {S_{\max} \times \frac{Ti}{T_{S2}}\left( {0 \leq {Ti} \leq T_{S2}} \right)}} & \left\lbrack {{Expression}8} \right\rbrack\end{matrix}$

Here, T_(s2) corresponds to a blocking time when the blocking timeincreases such that an increase in brightness is saturated, and S_(max)is S₀ at the blocking time T_(s2). The corrected brightness S_(c)relative to a residual charge can be obtained from Expression 9representing a time change in brightness when there is no residualcharge.

S _(C) =S _(max) ×e ^(−Tir/τ)  [Expression 9]

Further, the corrected brightness S_(c) can be obtained from Expression10 based on Expression 7, Expression 8, and Expression 9.

$\begin{matrix}{S_{C} = {S \times \frac{T_{S2}}{Ti}}} & \left\lbrack {{Expression}10} \right\rbrack\end{matrix}$

A variable value based on the influence of residual charge is correctedby calculation using Expression 10. As shown in a time change inbrightness and a corrected brightness 131 obtained at a first blockingtime and in a time change in brightness and a corrected brightness 132obtained at a second blocking time, the residual charge depending on theblocking time is corrected, and the corrected brightness values are thesame at the first blocking time and the second blocking time.

FIG. 17 shows an operation interface in the inspection recipe settingprocess used in the present embodiment. The operation interface has thesame configuration as that shown in FIG. 4 . In the present embodiment,a pattern a, a pattern b, and a pattern c are selected as targets to beinspected in the inspection pattern setting unit 61. In addition, in theacceleration voltage setting unit 63, the irradiation current settingunit 64, the field-of-view size setting unit 65, and the scanning speedsetting unit 66, the acceleration voltage is set to 300 V, theirradiation current is set to 1000 pA, the size of the field of view isset to 1 μm, and the scanning speed is set to a rate that is two times aTV rate.

In the present embodiment, as setting units of a plurality ofintermittent conditions, the operation interface includes: anirradiation time setting unit 141 that inputs a variable range of anirradiation time and a variable step thereof; and a blocking timesetting unit 141 that inputs a variable range of a blocking time and avariable step thereof.

When an increase in brightness is saturated, the blocking time T_(s2) is3.0 μs, and the amount of correction by residual charge can be extractedfrom each of the pattern a, the pattern b, and the pattern c in abrightness analysis result display unit 144 of the blocking time. Thecapacitance C can be analyzed from the corrected brightness obtainedfrom Expression 10 and Expression 3.

In the present embodiment, the flowchart of the inspection process ofclassifying defects shown in FIG. 5 is used. In the present embodiment,the operation interface of the defect inspection process shown in FIG. 9is used. Under the inspection conditions set in the inspection recipesetting process, the plug 121 as a normal plug, the plug 122 as adefective plug, and the plug 123 as a defective plug can be classifiedand inspected.

In the embodiment described above, by correcting the brightnessaccording to the electrical characteristics, the electrical resistance Rand the capacitance C of a defect can be analyzed with high accuracy.Therefore, the accuracy of defect classification is improved.

Embodiment 5

As described above, a change in brightness (for example, a signal amountat a specific position) depending on a change in beam irradiationcondition varies depending on electrical characteristics correspondingto the defect type. That is, a change in brightness obtained when a beamis irradiated under a plurality of beam irradiation conditions dependson electrical characteristics such as the defect type or thecharacteristic amount of a defect. For example, it can be said thatthere is a correlation between a combination of the irradiationconditions and characteristic amounts (or image data itself) obtainedfrom a plurality of images and electrical characteristics.

Therefore, in the present embodiment, a system that outputs electricalcharacteristics by inputting a plurality of irradiation conditions andat least one of image data acquired by beam irradiation under theirradiation conditions, characteristic amounts extracted from the imagedata, and information such as the S-curve into a learning device will bedescribed, the learning device executing learning in advance usingteacher data including a plurality of irradiation conditions, image dataacquired by beam irradiation under the irradiation conditions,characteristic amounts extracted from the image data, or informationsuch as the S-curve generated from the characteristic amounts as aninput and including electrical characteristics as an output.

FIG. 20 is a diagram showing one example of an electrical characteristicestimation system. FIG. 20 is a functional block diagram. A computersystem 2001 shown in FIG. 20 is a machine learning system, includes oneor more processors, and is configured to execute one or more arithmeticmodules stored in a predetermined storage medium. In addition, anestimation process described below may be performed using an AIaccelerator. The computer system 2001 shown in FIG. 20 includes an inputunit 2004 to which includes the teacher data provided for learning ordata required for the estimation process is input from a storage medium2002 or an input device 2003.

A learning unit 2005 built in the computer system 2001 receives, as theteacher data, a combination of at least one of image data input from theinput unit 2004 and a characteristic of an image extracted from an imageprocessing apparatus (not shown), a beam irradiation condition of thecharged particle beam apparatus, and electrical characteristicinformation of an element formed on a sample. The characteristic of theimage is, for example, brightness or a contrast of a specific patternand can be obtained by extracting brightness information of a patternspecified by pattern matching or the like or a specific patternsegmented by semantic segmentation or the like. As the learning device,for example, a neural network, a regression tree, or a Bayes identifiercan be used.

In addition, the beam irradiation condition is a blocking time or anirradiation time of a pulsed beam as described in the previousembodiment. The learning unit 2005 reads the inspection recipe from thecharged particle beam apparatus or receives an input from the inputdevice 2006 to receive this data as a part of the teacher data. Theelectrical characteristic information is, for example, a value obtainedby simulation, a value actually measured by an EB tester or the like, avalue obtained from an image that is obtained based on cross-sectionalprocessing observation of an actual device, or a value corresponding tothe defect type based on an experience of an operator, and the learningunit 2005 receives at least one piece of the information as a label.

The learning unit 2005 executes machine learning using the receivedteacher data. A learning model storage unit 2007 stores a learning modelthat is constructed by the learning unit 2005. The learning modelconstructed by the learning unit 2005 is transmitted to an electricalcharacteristic estimation unit 2008 and is used for estimatingelectrical characteristics.

In the electrical characteristic estimation unit 2008, based on thelearning model constructed by the learning unit 2005, electricalcharacteristics are estimated from the beam irradiation condition and atleast one of the image data and the characteristic extracted from theimage data. As described in the previous embodiment, a variation of thecharacteristic that can be recognized on the image when the beamirradiation condition is changed depends on the type of electricalcharacteristics or the parameter of electrical characteristics.Therefore, by allowing the learning device to execute learning using theelectrical characteristic information and a data set of the image dataor the like and the beam irradiation condition in advance, theelectrical characteristic can be estimated using the learning device.

The estimation result can be stored in an estimation result storage unit2009 or can be displayed on a display device included in an inputdevice.

The teacher data can include at least one of the electrical resistanceand the capacitance. Further, it is also thought that comparisoninformation (for example, size information relative to a standard value)of the electrical resistance or the capacitance is included in teacherdata.

FIG. 25 shows input data in the present embodiment. B represents apattern having a reference electrical resistance and a referencecapacitance, and A, C, D, and E are patterns having electricalcharacteristics different from that of B. In the four patterns A, C, D,and E, two defect types including a capacitance defect and an electricalresistance defect are mixed. In the present embodiment, regarding thefive patterns including A, C, D, E, and B, by inputting brightness at aplurality of blocking times (times at which a pulsed beam is notirradiated), two defect types including a capacitance defect and anelectrical resistance defect are classified. The input brightness is anaverage brightness in an image region specified by pattern matching orthe like. The learning device executes machine learning by usingregression analysis in which Expression 1, Expression 3, and Expression4 are used as model formulae and a neural network that weights theregression analysis results in combination. As a result of the machinelearning, the patterns A and C are output as capacitance defects, and Dand E are output as electrical resistance defects. The output resultmatches the classification result of an image obtained based oncross-sectional processing observation of an actual device.

In the above-described embodiment, the system that outputs electricalcharacteristics by inputting a plurality of irradiation conditions andat least one of image data acquired by beam irradiation under theirradiation conditions and characteristic amounts extracted from theimage data can be provided, and the defect type can be classified.

Embodiment 6

-   -   (a) of FIG. 21 is a cross-sectional view showing a simple        configuration of a transistor to be evaluated by the charged        particle beam apparatus or the like. Diffusion layers 2102 and        2103 are stacked on a well 2101, and a gate electrode 2105 is        formed over the diffusion layers 2102 and 2103 through a gate        oxide film 2104. In addition, a side wall 2106 is formed on a        side wall of the gate electrode 2105. Further, an electrode (a        source contact 2108 (first terminal), a gate contact 2109        (second terminal), and a drain contact 2110 (second terminal))        in contact with each of the diffusion layer 2102, the gate        electrode 2105, and the diffusion layer 2103 is formed with an        interlayer oxide film 2107 interposed therebetween.    -   (b) to (d) of FIG. 21 are diagrams showing the types of defects        of the transistor shown in (a) of FIG. 21 . (b) of FIG. 21 shows        a state (open defect) where the gate electrode 2105 and the gate        contact 2109 that are supposed to be connected to each other are        not connected. (c) of FIG. 21 shows a state (gate leakage        defect) where a current leaks from the gate electrode 2105. (d)        of FIG. 21 shows a state (junction leakage defect) where a        current leaks from the diffusion layer.

The system or the like for specifying a defect of a semiconductorelement will be described below. FIG. 22 is a flowchart showing aninspection process. In the present embodiment, an example of executinginspection based on image acquisition using the scanning electronmicroscope shown in FIG. 1 will be described. In the present embodiment,in order to specify the defect type, an image is formed based on beamirradiation on a region including a plurality of patterns (in thepresent embodiment, the source contact 2108, the gate contact 2109, andthe drain contact 2110 (hereinafter, also referred to as a plug)).

As in Step 106 of FIG. 3 , images are formed by beam irradiation at aplurality of blocking times (Steps 2201 and 2202), a set number ofimages (blocking conditions) are acquired, and characteristics areextracted from the acquired plurality of images (Step 2203). Here, thecharacteristic is, for example, a contrast relative to brightness of theplug or reference brightness.

The left of (a) of FIG. 23 shows one example of images of a plurality ofplugs having no defects. Three patterns that are aligned represent thesource contact, the gate contact, and the drain contact, in order fromthe left. When a beam is irradiated under a beam irradiation condition A(an irradiation condition where charge is more likely to be accumulatedthan a beam irradiation condition B described below; for example, apulsed beam having a shorter blocking time than that of the beamirradiation condition B), the charge is accumulated and the brightnessis low in the gate contact at the center. A pattern indicated by anoblique line shows a state where the brightness is lower than that in awhite pattern. On the other hand, when charge is accumulated in the gatecontact, the gate is opened. Therefore, the source contact and the draincontact are electrically connected, and the brightness of the left andright plugs is high.

On the other hand, when a transistor having no defects is irradiatedwith a beam under the beam irradiation condition B (an irradiationcondition where charge is less likely to be accumulated than the beamirradiation condition A), images are obtained as shown in the right of(a) of FIG. 23 . Due to the beam irradiation condition where charge isless likely to be accumulated, the brightness of the gate contact ishigh, but the gate is closed. Therefore, charge is accumulated and thebrightness is low in the source contact and the drain contact.

The left of (b) of FIG. 23 is a diagram showing an image example that isobtained when a plurality of patterns including a plug having an opendefect are irradiated with the beam under the beam irradiation conditionA. In the case of the open defect, even when the gate contact isirradiated with the beam, the gate is not opened and the gate contact isalso insulated. Therefore, the brightness of all the patterns is low. Onthe other hand, the right of (b) of FIG. 23 is a diagram showing animage example that is obtained when a plurality of patterns including aplug having an open defect are irradiated with the beam under the beamirradiation condition B. Due to the beam irradiation condition wherecharge is less likely to be charged, the brightness of the gate contactis high, but the gate is closed. Therefore, charge is sufficientlyaccumulated and the brightness is low in the source contact and thedrain contact.

The left of (c) of FIG. 23 is a diagram showing an image example that isobtained when a plurality of patterns having a gate leakage defect areirradiated with the beam under the beam irradiation condition A. Since acurrent leaks from the gate, charge is not accumulated in the gatecontact, and the brightness of the gate contact is high. Since the gateis not opened, charge is accumulated in the source contact and the draincontact, and the brightness thereof is lower than that of the gatecontact. On the other hand, the right of (c) of FIG. 23 is a diagramshowing an image example that is obtained when a plurality of patternshaving a gate leakage defect are irradiated with the beam under the beamirradiation condition B. In the gate contact, since charge is notaccumulated as shown in the left of (c) of FIG. 23 , the brightness ishigh but the gate is closed. Therefore, charge is sufficientlyaccumulated and the brightness is low in the source contact and thedrain contact.

The left of (d) of FIG. 23 is a diagram showing an image example that isobtained when a plurality of patterns having a junction leakage defectare irradiated with the beam under the beam irradiation condition A. Inthe case of the junction leakage defect, even when the source contactand the drain contact are irradiated with the beam, charge is notaccumulated. Therefore, the brightness of the patterns is high. Inaddition, since the gate contact is normal, charge is accumulated andthe brightness of the pattern is low as shown in (a) of FIG. 23 . On theother hand, the right of (d) of FIG. 23 is a diagram showing an imageexample that is obtained when a plurality of patterns having a junctionleakage defect are irradiated with the beam under the beam irradiationcondition B. In the source contact and the drain contact, charge is notaccumulated as shown in the left of (d) of FIG. 23 , and thus thebrightness thereof is high. In the gate contact, the accumulation ofcharge is small, and thus the brightness is higher than that shown inthe left of (d) of FIG. 23 .

As described above, a plurality of characteristics of a plurality ofpatterns forming a semiconductor element (in this example, a transistor)are combined according to defect types, the characteristics beingextracted from a plurality of images acquired under different beamconditions. Accordingly, for example, characteristic combinationinformation and defect type information are stored in the storage mediumof the computer system 2001 in association with each other. By comparing(Step 2204) the relation information (reference information) and aplurality of characteristics extracted from the acquired plurality ofimages to each other, the defect type can be specified (Step 2205). Forexample, the relation information is a table that defines a defect typeand a combination of characteristics. By referring to the table for aplurality of characteristics, a defect type having characteristics thatmatch or are most similar to the characteristics may be selected.

In addition, instead of the absolute value of brightness, a relationshipbetween a relationship of brightness of a plurality of patterns anddefect types may be stored as a library, and a defect type may bespecified by referring to the library.

In the description of a defect type or characteristics, some exampleshave been merely introduced. However, the method of specifying a defecttype using the information describing the relationship between defecttypes and characteristics of a plurality of patterns obtained under aplurality of beams having different charging conditions is alsoapplicable, for example, to specify other defect types.

The defect type described in the present embodiment can also beestimated using the learning device shown in FIG. 20 . For example, itis thought that a learning model that learns in advance is prepared, inwhich a plurality of beam irradiation conditions, plural pieces of imagedata obtained under a plurality of beam conditions, or a combination ofcharacteristics extracted from patterns and defect types are teacherdata, and a defect type is estimated by inputting beam irradiationconditions, plural pieces of image data, or characteristic amountcombination information into the learning model.

Embodiment 7

The transistor shown in FIG. 21 is an element that applies a voltage toa gate to adjust a current flowing between a source and a drain. Onemethod of process control of a semiconductor device is a method ofcontrolling input/output characteristics that is a relationship betweenan input and an output when the input is a voltage applied to theelement and the output is a current flowing through the element. In thepresent embodiment, a computer system that inspects input/outputcharacteristics of a semiconductor element will be described.

FIG. 24 is a graph in which the brightness of a plug is plotted, thebrightness being specified from images acquired by beam irradiationunder a plurality of beam conditions. In the present embodiment, thecharge accumulation state is adjusted by changing the blocking time of apulsed beam. (a) of FIG. 24 shows the transition of the brightness of agate contact, and (b) of FIG. 24 shows the transition of the brightnessof a source contact or a drain contact. The brightness of (a) of FIG. 24is inversely proportional to a voltage applied to the gate, and thebrightness of (b) of FIG. 24 is proportional to a current flowingbetween the source and the drain. Therefore, a combination of (a) and(b) of FIG. 24 is one form representing the input/outputcharacteristics.

In (a) of FIG. 24 , as the amount of charge accumulated increases, thebrightness decreases. On the other hand, in (b) of FIG. 24 , thebrightness rapidly increases from a given amount of charge accumulated.A rapid increase in brightness in (b) of FIG. 24 shows a change from astate where the gate is closed to a state where the gate is opened. Theprocessor included in the computer system generates a curve (informationgenerated from a plurality of characteristics) representing a change inbrightness relative to a change in image acquisition condition andspecifies a rapid change point in brightness, so that a gate thresholdvoltage that is one index representing input/output characteristics canbe specified.

In the computer system, for example, the displacement point is specifiedbased on differential processing of a waveform, and the gate thresholdis compared to previously registered reference information of anon-defective product or a defective product to determine whether or notthe gate threshold is appropriate. Specifically, for example, athreshold range (range of a beam irradiation condition) where anon-defective product can be obtained is stored in a predeterminedstorage medium in advance, and whether the product is non-defective ordefective is determined based on whether or not the displacement pointis included in the range. In addition, an S-curve (the curve shown inFig. (b) of 24) of a non-defective product or a defective product ispreviously registered as reference data, and whether or not the productis non-defective or defective may be determined by fitting theinspection result to the reference data. In addition, relationinformation regarding a relationship between a beam condition and a gatethreshold voltage is stored in advance, and a gate threshold may becalculated by referring to the relation information for the displacementpoint.

In the present embodiment, input/output characteristics of an elementformed on a semiconductor device can be evaluated.

In the present embodiment, the transistor such as MOSFET has beendescribed as an example. However, the above-described method isapplicable to an operation test of a memory (other switching elements)such as STT-MRAM. Specifically, input/output characteristics of aSTT-MRAM such as a switching speed, a drive current, or a write/erasethreshold may be obtained from the transition of the brightness of acontact plug obtained when a magnetic tunnel junction element ofSTT-MRAM is irradiated with a beam under a plurality of irradiationconditions.

In addition, input/output characteristics can be estimated using thelearning device shown in FIG. 20 . For example, it is thought that alearning model that learns in advance is prepared, in which a pluralityof beam irradiation conditions, plural pieces of image data obtainedfrom a plurality of beam conditions, or a combination (S-curve) ofcharacteristics extracted from patterns and input/output characteristicinformation are teacher data, and input/output characteristics isestimated by inputting beam irradiation conditions, plural pieces ofimage data, or a S-curve into the learning model.

REFERENCE SIGNS LIST

-   -   1: electron beam source    -   2: condenser lens    -   3: diaphragm    -   4: pulsed electron generator    -   5: deflector    -   6: objective lens    -   7: sample electric field controller    -   8: detector    -   9: output adjustment circuit    -   10: sample stage    -   11: sample    -   21: acceleration voltage controller    -   22: irradiation current controller    -   23: pulse irradiation controller    -   24: deflection controller    -   25: focusing controller    -   26: sample electric field controller    -   27: stage position controller    -   28: control transmitter    -   29: stage position controller    -   30: control transmitter    -   31: detection signal processing unit    -   32: detection signal analysis unit    -   33: image or electrical characteristic display unit    -   34: database    -   41: operation interface    -   51: plug    -   52: plug    -   53: silicon substrate    -   54: plug    -   55: plug    -   61: inspection pattern setting unit    -   62: optical condition/scanning condition/field of view setting        unit    -   63: acceleration voltage setting unit    -   64: irradiation current setting unit    -   65: field-of-view size setting unit    -   66: scanning speed setting unit    -   67: intermittent condition extraction unit    -   68: irradiation setting unit    -   69: inter-irradiation point setting unit    -   70: brightness analysis result display unit    -   71: inspection condition setting unit    -   72: irradiation setting unit used for inspection    -   73: inter-irradiation point setting unit used for inspection    -   74: trial inspection execution unit trial inspection result        display unit    -   81: inspection region setting unit    -   82: inspection execution unit    -   83: defect classification setting unit    -   84: defect a group generating distribution display unit    -   85: defect b group generating distribution display unit    -   86: defect group generating distribution display unit    -   91: plug    -   92: silicon substrate    -   93: impurity diffusion layer    -   94: plug    -   95: plug    -   96: plug    -   101: plug    -   102: plug    -   103: plug    -   104: wiring    -   105: wiring    -   106: silicon substrate    -   111: time change of brightness obtained at first irradiation        time    -   112: time change of brightness obtained at second irradiation        time    -   113: time change of brightness obtained at third irradiation        time    -   114: time change of brightness obtained at first to third        irradiation times    -   115: time change of corrected brightness    -   121: plug    -   122: plug    -   123: plug    -   1124: impurity diffusion layer    -   125: silicon substrate    -   131: time change in brightness and corrected brightness obtained        at first blocking time    -   132: time change in brightness and corrected brightness obtained        at second blocking time    -   141: irradiation time setting unit    -   142: blocking time setting unit    -   143: brightness analysis result display unit of irradiation time    -   144: brightness analysis result display unit

1. A system comprising: a charged particle beam apparatus that acquiresan image of a sample; and a computer system that includes one or moreprocessors and is configured to be communicable with the chargedparticle beam apparatus; wherein the computer system includes a memorythat stores relation information related to information regarding two ormore characteristics and reference information of a non-defectiveproduct or a defective product of a switching element formed on thesample, the characteristics being extracted from at least two pieces ofimage data acquired from the charged particle beam apparatus under atleast two beam irradiation conditions, wherein the one or moreprocessors receives information regarding two or more characteristics ofa specific pattern included in a plurality of pieces of image dataacquired from the charged particle beam apparatus under at least twodifferent beam irradiation conditions, the beam irradiation conditionsincluding at least one of a blocking time and an irradiation time of abeam when the sample is irradiated with the beam in a pulsatile mannerusing the charged particle beam apparatus, receives the relationinformation from the memory, and evaluates input/output characteristicsof the switching element or determines whether the switching element isa non-defective product or a defective product, based on the relatedinformation and a displacement point of change in the informationregarding two or more characteristics of the specific pattern includedin the plurality of pieces of image data.
 2. The system according toclaim 1, wherein the input/output characteristics are related to atleast one of a gate threshold voltage, a switching speed, a drivecurrent, and a write/erase threshold.
 3. The system according to claim1, wherein the memory stores the related information between changes ina plurality of beam irradiation conditions with different blocking timeand irradiation time, and changes of the characteristics.
 4. The systemaccording to claim 1, wherein evaluating the input/outputcharacteristics includes identifying, displaying, managing, orestimating the input/output characteristics.
 5. The system according toclaim 1, wherein the displacement point of change in the informationregarding two or more characteristics of the specific pattern includedin the plurality of pieces of image data is the displacement point ofchange in the information regarding two or more brightnesses of thespecific pattern included in the plurality of pieces of image data.
 6. Anon-transitory computer-readable medium storing a program configured toinstruct a processor to: receive information regarding two or morecharacteristics of a specific pattern included in a plurality of piecesof image data acquired from a charged particle beam apparatus under atleast two different beam irradiation conditions, receive relationinformation related to information regarding two or more characteristicsand reference information of a non-defective product or a defectiveproduct of a switching element formed on a sample, the characteristicsbeing extracted from at least two pieces of image data acquired from thecharged particle beam apparatus under at least two beam irradiationconditions, the beam irradiation condition being at least one of ablocking time and an irradiation time of a beam when the sample isirradiated with the beam in a pulsatile manner using the chargedparticle beam apparatus, and evaluate input/output characteristics ofthe switching element or determine whether the switching element is anon-defective product or a defective product, based on the relatedinformation and a displacement point of change in the informationregarding two or more characteristics of the specific pattern includedin the plurality of pieces of image data.
 7. The non-transitorycomputer-readable medium according to claim 6, wherein the input/outputcharacteristics are related to at least one of a gate threshold voltage,a switching speed, a drive current, and a write/erase threshold.
 8. Asystem for estimating input/output characteristics of a switchingelement formed on a sample from image data acquired by a chargedparticle beam apparatus, the system comprising: a computer system; andan arithmetic module that is executed by the computer system; whereinthe computer system includes a learning unit that outputs theinput/output characteristics of the switching element as a learningresult, wherein the learning unit executes learning in advance usingteacher data including at least one among at least two pieces of imagedata acquired from the charged particle beam apparatus under at leasttwo beam irradiation conditions, two or more characteristics extractedfrom the two or more pieces of image data, and a displacement point ofchange in information generated from the two or more characteristics, atleast two beam irradiation conditions of the charged particle beamapparatus, and input/output characteristics, the beam irradiationcondition being at least one of a blocking time and an irradiation timeof a beam when the sample is irradiated with the beam in a pulsatilemanner using the charged particle beam apparatus, and the arithmeticmodule evaluates input/output characteristics of the switching elementor determines whether the switching element is a non-defective productor a defective product by inputting, to the learning unit, at least oneamong at least two pieces of image data acquired from the chargedparticle beam apparatus under at least two beam irradiation conditions,two or more characteristics extracted from the two or more pieces ofimage data, and a displacement point of change in information generatedfrom the two or more characteristics, and at least two beam irradiationconditions of the charged particle beam apparatus.
 9. The systemaccording to claim 8, wherein the input/output characteristics arerelated to at least one of a gate threshold voltage, a switching speed,a drive current, and a write/erase threshold.
 10. A system including oneor more processors and configured to be communicable with a chargedparticle beam apparatus, the system comprising: a memory that storesrelation information related to at least two beam irradiation conditionsof the charged particle beam apparatus, information regarding two ormore characteristics, and quality information of a switching elementformed on a sample, the characteristics being extracted from at leasttwo pieces of image data acquired from the charged particle beamapparatus under the at least two beam irradiation conditions, the beamirradiation conditions including at least one of a blocking time and anirradiation time of a beam when the sample is irradiated with the beamin a pulsatile manner using the charged particle beam apparatus; whereinthe one or more processors receives, from the charged particle beamapparatus, at least two different beam irradiation conditions, andinformation regarding two or more characteristics of a specific patternincluded in a plurality of pieces of image data acquired from thecharged particle beam apparatus under at least two different beamirradiation conditions, and evaluates input/output characteristics orquality of the switching element, based on the related information andchange in the information regarding two or more characteristics of thespecific pattern included in the plurality of pieces of image datacorresponding to change in the at least two different beam irradiationconditions.
 11. The system according to claim 10, wherein theinput/output characteristics are related to at least one of a gatethreshold voltage, a switching speed, a drive current, and a write/erasethreshold.
 12. The system according to claim 10, wherein the one or moreprocessors identify a displacement point of the information regardingtwo or more characteristics from the change in the information regardingthe characteristics of the specific pattern included in the plurality ofpieces of image data corresponding to change in the at least twodifferent beam irradiation conditions, and evaluate input/outputcharacteristics or quality of the switching element based on theidentified displacement point.